Question

Solve 4^x- 3 = 18. Round to the nearest thousandth.

Answer 1

4^(x- 3) = 18

ln[4^(x- 3)] = ln(18)

ln4(x - 3) = ln(18)

ln4x - ln4(3) = ln18

ln4x = ln18 + 3ln4

x = [ln18 + 3ln4]/ln4

x = 5.0849625007

x is approximately 5.085.